Hypothermia has been shown to provide distinct medical benefits to myocardial infarction, traumatic brain injury, stroke, cardiac arrest and other patients by limiting the size of the infarction and related tissue injury if initiated soon enough and if the level of cooling is significant enough. Both of these limitations—initiation of and depth of cooling—have made practical application of the technology quite challenging, particularly in an ambulance or other emergency settings in the field. Initiation of cooling, for example, is a major issue since most technologies require sophisticated machinery that would be difficult to place in ambulance, so the patient, at best, receives the hypothermic benefit some time after they reach the hospital. Of the technologies that can be initiated in the field, such as cooling blankets, cooling caps, etc., the depth of cooling is a major issue due to surface area limitations, complications (such as intense shivering response) and patient access issues (once the blanket is on, it may be difficult to access the patient).
In addition to externally applied cooling, hypothermia may be induced by cooling the interior of the subject's body, such as by accessing the vasculature or an internal cavity. See, e.g., U.S. Pat. No. 5,752,929; U.S. Pat. No. 5,709,654 and US 2007/0106247.